Lanceolanone A, a new biflavanone, and a chalcone glucoside from the flower heads of Coreopsis lanceolata and their aldose reductase inhibitory activity and AMPK activation.

The MeOH extract of the flower heads of Coreopsis lanceolata L. (Asteraceae) exhibited aldose reductase (AR) inhibitory activity (IC50 8.36 µg/mL). Bioassay-guided fractionation of the extract resulted in the isolation of a new biflavanone-named Lanceolanone A (1) and a chalcone glucoside (6), along with 12 known compounds (2-5 and 7-14), of which 4, 7, 9, 10, and 12 were isolated from C. lanceolata for the first time. The structures of the new compounds (1 and 6) were determined by extensive spectroscopic analysis, including two-dimensional (2D) NMR, and ECD calculation method. Compounds 2, 4, 11, 13, and 14 exhibited AR inhibitory activities with IC50 values between 2.40 and 9.99 µM. Furthermore, 8-13 at 1.0 mM activated AMPK expression in HepG2 human hepatoma cells compared to the control.

Cytotoxic triterpene and steroidal glycosides from the seeds of Digitalis purpurea and the synergistic cytotoxicity of steroidal glycosides and etoposide in SBC-3 cells.

The phytochemical investigations of the seeds of Digitalis purpurea have revealed their richness in cardenolide and pregnane glycosides exhibiting potent cytotoxicity; further chemical examinations of the D. purpurea seeds have achieved the isolation of six triterpene glycosides (1-6), six spirostanol glycosides (7-12), and three furostanol glycosides (13-15), including seven previously unidentified compounds (1-3, 10-12, and 14). Here, the structures of 1-3, 10-12, and 14 were determined via extensive spectroscopic analyses, including two-dimensional (2D) NMR; hydrolysis, followed by chromatographic and spectroscopic analyses; and X-ray crystallographic analysis. The cytotoxic activities of the isolated compounds (1-15) against SBC-3 small cell lung carcinoma and TIG-3 normal human diploid fibroblast cells were evaluated. Triterpene glycoside 3 and spirostanol glycoside 9 exhibited considerable cytotoxicity with IC50 values of 1.0 and 1.7 µM, respectively; they induced apoptotic cell death, which was accompanied by the activation of caspase-3 in SBC-3 cells. Spirostanol glycoside 7 exhibited cytotoxicity toward the SBC-3 cells (IC50 1.3 µM). Additionally, 7 at 0.1 and 1.0 µM synergistically enhanced the cytotoxicity of etoposide against SBC-3 cells; compound 7 induced the release of DAMPs; the release of HMGB1, the secretion of ATP, and the exposure of CALR in the SBC-3 cells. Furthermore, the combination of 7 and etoposide resulted in increasing the extracellular release of DAMPs. These data indicated that 7, as well as its combination with etoposide, might potentially cause immunogenic cell death.

Novel Oleanane-Type Triterpene Glycosides from the Saponaria officinalis L. Seeds and Apoptosis-Inducing Activity via Mitochondria.

Saponaria officinalis L., commonly known as "Soapwort", is a rich source of triterpene glycosides; however, the chemical constituents of S. officinalis seeds have not been fully identified. In this study, we conducted a systematic phytochemical investigation of the seeds of S. officinalis and obtained 17 oleanane-type triterpene glycosides (1-17), including seven new glycosides (1-7). The structures of 1-7 were determined based on a detailed analysis of NMR spectroscopic data and chromatographic and spectroscopic analyses following specific chemical transformation. The cytotoxicities of the isolated compounds were evaluated against HL-60 human promyelocytic leukemia cells, A549 human adenocarcinoma lung cancer cells, and SBC-3 human small-cell lung cancer cells. The cytotoxicities of 1, 4, and 10 toward HL-60 cells and SBC-3 cells were nearly as potent as that of cisplatin. Compound 1, a bisdesmosidic triterpene glycoside obtained in good yield, arrested the cell cycle of SBC-3 cells at the G2/M phase, and induced apoptosis through an intrinsic pathway, accompanied by ROS generation. As a result of the mitochondrial dysfunction induced by 1, mitochondria selective autophagy, termed mitophagy, occurred in SBC-3 cells.

Three novel furospirostanol glycosides and a steroidal alkaloid glycoside from the bulbs of Fritillaria camtschatcensis (L.) Ker Gawl., and their cytotoxicity.

Three novel steroidal glycosides (1-3) and a previously described steroidal alkaloid glycoside (4) have been isolated from the bulbs of Fritillaria camtschatcensis (L.) Ker Gawl. (Liliaceae). The structures of novel compounds 1-3 were characterized based on NMR spectroscopy and chemical transformations. Compounds 1-3 are furospirostanol glycosides bearing a (3S)-3-hydroxy-3-methylglutaryl moiety at C-26 in the aglycone. Compounds 1-4 were evaluated in terms of their cytotoxic activities toward HL-60 human promyelocytic leukemia cells, A549 human lung adenocarcinoma cells, and SBC-3 human lung small cell carcinoma cells. Only 4 showed moderate cytotoxicity against HL-60, A549, and SBC-3 cells with IC50 values of 22.9, 13.3, and 11.9 µM, respectively. Compound 4 was found to cause necrotic-like cell death in HL-60 cells.

A new and 23 known cardenolide glycosides from Thevetia neriifolia seeds and their cytotoxic activities against human oral carcinoma cell lines.

Phytochemical analysis of Thevetia neriifolia seeds resulted in the isolation of one new (1) and 23 known (2－24) cardenolide glycosides. The structure of 1 was determined based on one- and two-dimensional NMR spectroscopic analysis and acid hydrolytic cleavage reaction. The effect of the cytotoxic activity of 1－24 on three human oral carcinoma cell lines was assessed. The cell lines included Ca9-22 human gingival carcinoma cells, HSC-2 human mouth carcinoma cells, HSC-4 human tongue carcinoma cells, and HGF human gingival fibroblast cells. The isolated compounds had a cytotoxic effect on the carcinoma cells with IC50 values ranging from 0.004 µM to 64.9 µM. The structure-activity relationship is also discussed.

Steroidal constituents isolated from the seeds of Withania somnifera.

A new withanolide glycoside (1), two new ergostanol glycosides (2 and 3), and a new furostanol glycoside (4), along with nine known steroidal derivatives (5-12) were isolated from the seeds of Withania somnifera. The structures of the new compounds were determined using spectroscopic analysis and hydrolysis. The cytotoxic activities of the isolated compounds were evaluated against Ca9-22 human gingival carcinoma cells, HSC-2 human mouth carcinoma cells, and HL-60 human promyelocytic leukemia cells. Only 12 exhibited cytotoxic activity against these cell lines with IC50 values of 0.38, 0.54, and 1.5 µM, respectively.

Cholestane glycosides from Ornithogalum saundersiae bulbs and the induction of apoptosis in HL-60 cells by OSW-1 through a mitochondrial-independent signaling pathway.

A search for cytotoxic cholestane glycosides from Ornithogalum saundersiae bulbs resulted in the isolation of three new OSW-1 analogues (1-3), a new cholestane bisdesmoside (4), a 5ß-cholestane diglycoside (5), and four new 24(23 → 22)-abeo-cholestane glycosides (6-9), together with 11 known cholestane glycosides (10-20), including OSW-1 (11). The structures of 1-9 were determined based on conventional spectroscopic analysis and chemical evidence. As expected, based on previous data, 1-3 exhibited potent cytotoxic activity against HL-60 human promyelocytic leukemia cells and A549 human lung adenocarcinoma cells. Furthermore, the ability of OSW-1 to induce apoptosis in HL-60 cells was examined. Aggregation of nuclear chromatin, accumulation of the sub-G1 cells, DNA fragmentation, and caspase-3 activation were assessed in HL-60 cells treated with OSW-1, providing evidence for OSW-1-induced apoptosis in HL-60 cells. No mitochondrial membrane potential or release of cytochrome c into the cytoplasm were observed in the OSW-1-treated apoptotic HL-60 cells, indicating that a mitochondria-independent signaling pathway is involved in apoptotic cell death.

Structural Characterization of Cholestane Rhamnosides from Ornithogalum saundersiae Bulbs and Their Cytotoxic Activity against Cultured Tumor Cells.

Previous phytochemical studies of the bulbs of Ornithogalum saundersiae, an ornamental perennial plant native to South Africa, resulted in the isolation of 29 new cholestane glycosides, some of which were structurally unique and showed potent cytotoxic activity against cultured tumor cell lines. Therefore, we aimed to perform further phytochemical examinations of methanolic extracts obtained from Ornithogalum saundersiae bulbs, isolating 12 new cholestane rhamnosides (1-12) and seven known compounds (13-19). The structures of the new compounds (1-12) were identified via NMR-based structural characterization methods, and through a sequence of chemical transformations followed by spectroscopic and chromatographic analysis. The cytotoxic activity of the isolated compounds (1-19) and the derivatives (1a and 6a) against HL-60 human promyelocytic leukemia cells and A549 human lung adenocarcinoma cells was evaluated. Compounds 10-12, 16, and 17 showed cytotoxicity against both HL-60 and A549 cells. Compound 11 showed potent cytotoxicity with an IC50 value of 0.16 µM against HL-60 cells and induced apoptotic cell death via a mitochondrion-independent pathway.

Amurensiosides L-P, five new cardenolide glycosides from the roots of Adonis amurensis.

Five new cardenolide glycosides, amurensiosides L-P (1-5), were isolated from the roots of Adonis amurensis. Their structures were determined based on extensive spectroscopic analysis, including two-dimensional (2D) NMR data, and on the results of hydrolytic cleavage. Compounds 1-5 were evaluated for their cytotoxic activities against HL-60 human promyelocytic leukemia and HSC-2 human oral squamous cell carcinoma cell lines.

Karataviosides G-K, five new bisdesmosidic steroidal glycosides from the bulbs of Allium karataviense.

We have analyzed the steroidal glycosides in Allium karataviense bulbs, and isolated five new bisdesmosidic steroidal glycosides: karataviosides G-K (1-5). The structures were elucidated by extensive spectroscopic analysis, including 2D NMR and enzymatic and hydrolytic cleavage. Karatavioside G (1) is an entirely novel furostanol glycoside, which has an O-ß-d-glucopyranosyl-(1→6)-ß-d-glucopyranosyl-(1→6)-ß-d-glucopyranosyl unit at C-26 of the aglycone. Although a variety of cholestanol glycosides have been isolated, mainly from Liliaceae and Agavaceae, karataviosides J and K (4 and 5) are also notable because they are the most polar cholestanol bisdesmosides discovered, in which a lycotetraose is attached to C-3 of the aglycone, and a glucose or O-glucosyl-(1→3)-glucose is attached at C-16. The isolated glycosides were also evaluated for their cytotoxic activities against cultured tumor cell lines.

Cardenolide glycosides from the seeds of Digitalis purpurea exhibit carcinoma-specific cytotoxicity toward renal adenocarcinoma and hepatocellular carcinoma cells.

Four cardenolide glycosides, glucodigifucoside (2), 3'-O-acetylglucoevatromonoside (9), digitoxigenin 3-O-ß-D-glucopyranosyl-(1 → 4)-ß-D-glucopyranosyl-(1 → 4)-3-O-acetyl-ß-D-digitoxopyranoside (11), and purpureaglycoside A (12), isolated from the seeds of Digitalis purpurea, exhibited potent cytotoxicity against human renal adenocarcinoma cell line ACHN. These compounds exhibited significantly lower IC50 values against ACHN than that against normal human renal proximal tubule-derived cell line HK-2. In particular, 2 exhibited the most potent and carcinoma-specific cytotoxicity, with a sixfold lower IC50 value against ACHN than that against HK-2. Measurement of cyclin-dependent kinase inhibitor levels revealed that upregulation of p21/Cip1 expression was involved in the carcinoma-specific cytotoxicity of 2. Further, compound 2 also exhibited the carcinoma-specific cytotoxicity toward hepatocellular carcinoma cell line.

New cardenolide glycosides from the seeds of Digitalis purpurea and their cytotoxic activity.

A chemical investigation of Digitalis purpurea seeds led to the isolation of three new cardenolide glycosides (1, 8 and 11), together with 12 known cardenolide glycosides (2-7, 9, 10 and 12-15). The structures of 1, 8 and 11 were determined by 1D and 2D NMR spectroscopic analyses and the results of an acid or enzymatic hydrolysis. The cytotoxic activity of the isolated compounds (1-15) against HL-60 leukemia cells was examined. Compounds 2, 9, 11 and 12 showed potent cytotoxicity against HL-60 cells with respective 50% inhibition concentration (IC50) values of 0.060, 0.069, 0.038, and 0.034 µM. Compounds 2, 9 and 11 also exhibited potent cytotoxic activity against HepG2 human liver cancer cells with respective IC50 values of 0.38, 0.79, and 0.71 µM. An investigation of the structure-activity relationship showed that the cytotoxic activity was reduced by the introduction of a hydroxy group at C-16 of the digitoxigenin aglycone, methylation of the C-3' hydroxy group at the fucopyranosyl moiety, and acetylation of the C-3' hydroxy group at the digitoxopyranoyl moiety.

New cardenolides from the seeds of Adonis aestivalis.

Chemical investigation of the seeds of Adonis aestivalis has led to the isolation of a new cardenolide (3ß,5α,14ß,17ß-tetrahydroxycard-20,22-enolide) (1), two new glycosides (2, 3) of 1, and a new strophanthidin hexaglycoside (4), together with a known compound, strophanthidin 3-O-ß-D-glucopyranoside (5). The structures of 1-4 were determined by 1D- and 2D-NMR spectroscopic analysis and the results of hydrolytic cleavage. The isolated compounds (1-5) were examined for their cytotoxic activity against neoplastic HSC-2, HSC-3, HSC-4, and HL-60 cells, as well as HGF, HPLF, and HPC normal cell lines. Compounds 2, 4, and 5 were found to display selective cytotoxicity toward malignant tumor cell lines. Although the morphological observations of HL-60 and HSC-2 cell deaths by 2, 4, and 5 revealed changes characteristic of apoptosis, neither DNA degradation nor activation of caspase-3 was observed. Our findings demonstrated that 2, 4, and 5 may trigger caspase-3-independent apoptotic cell death in HL-60 and HSC-2 cells.

Natural products reveal cancer cell dependence on oxysterol-binding proteins.

Cephalostatin 1, OSW-1, ritterazine B and schweinfurthin A are natural products that potently, and in some cases selectively, inhibit the growth of cultured human cancer cell lines. The cellular targets of these small molecules have yet to be identified. We have discovered that these molecules target oxysterol binding protein (OSBP) and its closest paralog, OSBP-related protein 4L (ORP4L)--proteins not known to be involved in cancer cell survival. OSBP and the ORPs constitute an evolutionarily conserved protein superfamily, members of which have been implicated in signal transduction, lipid transport and lipid metabolism. The functions of OSBP and the ORPs, however, remain largely enigmatic. Based on our findings, we have named the aforementioned natural products ORPphilins. Here we used ORPphilins to reveal new cellular activities of OSBP. The ORPphilins are powerful probes of OSBP and ORP4L that will be useful in uncovering their cellular functions and their roles in human diseases.

Amurensiosides A-K, 11 new pregnane glycosides from the roots of Adonis amurensis.

Five new pregnane tetraglycosides, amurensiosides A-E (1-5), two new pregnane hexaglycosides, amurensiosides F (6) and I (9), two new 18-norpregnane hexaglycosides, amurensiosides G (7) and H (8), and two new pregnane octaglycosides, amurensiosides J (10) and K (11), were isolated from the MeOH extract of the roots of Adonis amurensis. The structures of the new compounds were determined on the basis of extensive spectroscopic analysis, including two-dimensional (2D) NMR data, and the results of hydrolytic cleavage. The isolated compounds were evaluated for their cytotoxic activity against HSC-2 human oral squamous cell carcinoma cells.

Sesquiterpenoids and flavonoids from the aerial parts of Tithonia diversifolia and their cytotoxic activity.

Cytotoxicity-guided fractionation of the 80% EtOH extract of Tithonia diversifolia has resulted in the isolation of twelve sesquiterpenoids (1-12), including three new ones (4, 10, 12), and three known flavonoids (13-15). The structures of the new compounds were determined by analysis of their spectroscopic data. The isolated compounds showed cytotoxic activity against HL-60 leukemia cells with IC(50) values ranging from 0.13 to 13.0 microM, when etoposide used as a positive control gave an IC(50) value of 0.43 microM. The cancer growth inhibitory property of 9, the main cytotoxic compound in T. diversifolia, was examined using a disease-oriented panel composed of 39 human cancer cell lines in the Japanese Foundation for Cancer Research.

Convallasaponin A, a new 5beta-spirostanol triglycoside from the rhizomes of Convallaria majalis.

The rhizomes of Convallaria majalis have been analyzed for their steroidal glycoside constituents, resulting in the isolation of a new 5beta-spirostanol triglycoside, named convallasaponin A, along with two known cardenolide glycosides and a known cholestane glycoside. The structure of convallasaponin A was determined on the basis of extensive spectroscopic analysis, including 2D NMR data, and the results of hydrolytic cleavage. The cardenolide glycosides showed tumor specific cytotoxic activity.

Oleanane and taraxerane glycosides from the roots of Gomphrena macrocephala.

Phytochemical screening of the roots of Gomphrena macrocephala, with particular attention to its triterpene glycoside constituents, has resulted in the isolation of two new oleanane glycosides (1 and 2) and a new taraxerane glycoside (3). The structures of 1-3 were determined as 11alpha,12alpha-epoxy-3beta-[(O-beta-D-glucuronopyranosyl)oxy]olean-28,13-olide (1), 11alpha,12alpha-epoxy-3beta-[(O-beta-D-galactopyranosyl-(1-->3)-O-[beta-D-glucopyranosyl-(1-->2)]-beta-D-glucuronopyranosyl)-oxy]olean-28,13-olide (2), and 11alpha,12alpha-epoxy-3beta-[(O-beta-D-glucuronopyranosyl)oxy]taraxer-14-en-28-oic acid beta-D-glucopyranosyl ester (3), respectively, on the basis of their spectroscopic data and the results of hydrolysis. The aglycones (1a and 3a) of 1-3 with an epoxy group showed cytotoxic activity against HSC-2 human oral squamous carcinoma cells.

Curcuminoids and sesquiterpenoids in turmeric (Curcuma longa L.) suppress an increase in blood glucose level in type 2 diabetic KK-Ay mice.

Turmeric, the rhizome of Curcuma longa L., has a wide range of effects on human health. The chemistry includes curcuminoids and sesquiterpenoids as components, which are known to have antioxidative, anticarcinogenic, and antiinflammatory activities. In this study, we investigated the effects of three turmeric extracts on blood glucose levels in type 2 diabetic KK-A(y) mice (6 weeks old, n = 5/group). These turmeric extracts were obtained by ethanol extraction (E-ext) to yield both curcuminoids and sesquiterpenoids, hexane extraction (H-ext) to yield sesquiterpenoids, and ethanol extraction from hexane-extraction residue (HE-ext) to yield curcuminoids. The control group was fed a basal diet, while the other groups were fed a diet containing 0.1 or 0.5 g of H-ext or HE-ext/100 g of diet or 0.2 or 1.0 g of E-ext/100 g of diet for 4 weeks. Although blood glucose levels in the control group significantly increased (P < 0.01) after 4 weeks, feeding of 0.2 or 1.0 g of E-ext, 0.5 g of H-ext, and 0.5 g of HE-ext/100 g of diet suppressed the significant increase in blood glucose levels. Furthermore, E-ext stimulated human adipocyte differentiation, and these turmeric extracts had human peroxisome proliferator-activated receptor-gamma (PPAR-gamma) ligand-binding activity in a GAL4-PPAR-gamma chimera assay. Also, curcumin, demethoxycurcumin, bisdemethoxycurcumin, and ar-turmerone had PPAR-gamma ligand-binding activity. These results indicate that both curcuminoids and sesquiterpenoids in turmeric exhibit hypoglycemic effects via PPAR-gamma activation as one of the mechanisms, and suggest that E-ext including curcuminoids and sesquiterpenoids has the additive or synergistic effects of both components.

27-norlanostane glycosides from the bulbs of Muscari paradoxum.

Eight 27-norlanostane glycosides (1-8), including five new compounds (3 and 5-8), were isolated from the MeOH extract of the bulbs of Muscari paradoxum. The structures of the new compounds were determined on the basis of extensive spectroscopic analysis, including 2D NMR data, and the results of hydrolytic cleavage. The cytotoxic activity of 1-8 against HSC-2 human oral squamous cell carcinoma cells is also reported.